Such a device is already known (German Pat. No. 1,635,899). It comprises a rotatable storage drum with longitudinal slits open at one end of said drum. The sliding disc can be tilted on the drum axle about a pin extending transversely through the latter and is mounted for rotation with the drum by means of ball bearings in such a manner that it is located substantially within the drum wall. On its circumference the disc comprises arms extending outwardly through the longitudinal slits in the drum wall. The inclined position of the sliding disc is determined firstly by a spring engaging thereon, and secondly by the thread supply on the drum wall which acts on the arms, and is used to actuate a switch which switches the drum drive on or off depending on the size of the thread supply.
There is also a known thread storing and feeding device for positive thread feeding (German Offenlegungsschrift No. 2,159,155) in which the storage drum is designed as a cage of rods inside which the sliding disc is arranged with arms extending through the intermediate spaces in the cage. In addition, there are known thread storing and feeding devices comprising a stationary drum and a thread guide which can be rotated about the storage drum to take up the thread, each of which devices likewise comprises a storage drum with longitudinal slits in the walls and a plate obliquely mounted inside the wall with arms extending outwardly through the slits. A feature common to all the previously described known devices is that the drum wall is broken up by numerous longitudinal slits or, in the case of the cage design, intermediate spaces or gaps. It does not therefore have any high strength properties, particularly if the longitudinal slits are open at one end of the drum.
The problem for the invention is to provide a thread storing and feeding device of the type described at the beginning, which comprises a storage drum of sturdy design and with which reliable take-up of the thread windings on the drum is still ensured simply by the sliding disc.
The problem is solved in accordance with the invention in that the storage drum comprises a wall closed on the circumference with longitudinal grooves on the outside, and the sliding disc has an edge overlapping the upper edge of the storage drum and webs, teeth or fingers extending inwardly into the longitudinal grooves in the drum.
The closed drum wall is solid and non-deformable. These properties are further improved by the webs having the full thickness of the wall being left between the grooves. Manufacture is no more costly than manufacture of a slotted drum wall and more economical than making a rodlike cage closed at the top, and assembly is simpler. A further advantage of the closed drum wall is that unavoidable worn particles of thread and the like cannot settle in the grooves as between slits, nor can they reach the interior of the drum. Depending on whether the drum and sliding disc are rotatable or stationary, the disc according to the invention can be mounted on the drum axle in the same manner as is known for sliding discs which have arms extending through the drum wall. The only requirement is that either the bearing be set slightly higher in relation to the drum and/or the sliding disc be bent at an angle to fit over the edge of the drum. The sliding disc can be mounted so as to be vertically movable in known manner or tiltable depending on the thread supply and spring load, the movements of the said disc being used to control take-up of the thread.
The longitudinal grooves can have a maximum depth of approximately two-thirds of the thickness of the drum wall. The webs, teeth or fingers of the sliding disc are thus provided with sufficient play or space necessary for sliding discs which vary their angle of inclination relative to the drum axle. Firstly, engagement of the webs, etc. in the upward pivoted section should be maintained as far as possible, and secondly the webs, etc. in the downward pivoted section should not be firmly fixed on the drum wall.
Embodiments of thread storing and feeding devices according to the invention are illustrated in the drawings.